Could Honda's Future 1.0-Liter Be World's Most Efficient Engine?

The last time Honda made a 1.0-liter gasoline engine, it broke new records for fuel efficiency.

Found under the hood of the original Insight hybrid, it still has the highest gas mileage of any EPA-rated non-plugin. It also took International Engine of the Year in 2000, and won that competition's sub-1-liter class seven times.

That's a high bar to aim for, but Honda says its latest 1.0-liter engine could set new records for gasoline engine efficiency.

According to The Financial Express(via Indian Autos Blog), the Japanese automaker is currently working on a global small engine for use in a new small car due for launch in 2017.

It will be available in both naturally-aspirated and turbocharged formats. The latter could find its way into some of Honda's bigger small-cars, like the Fit, in some markets.

At the moment, Honda's smallest regular gasoline unit is a 1.2-liter four-cylinder used in the Brio, a subcompact sold in markets like India, Thailand and Indonesia. In local tests, it achieves mileage of 46 mpg combined.

The new engine would find its way into cars aimed at similar markets, complementing a 1.5-liter turbocharged diesel also sold in Far-Eastern countries where diesel power is highly desirable.

The company does of course produce smaller 660cc gasoline engines for its kei-car range, though these vehicles are sold only in Japan.

Honda itself is not yet commenting on the new unit, so it's unclear whether it will take the form of a three- or four-cylinder unit.

The company's last 1.0, as used in the Insight, was a development of the three-cylinder line used in the company's kei-cars. It displaced 995cc and its 12 valves were operated using Honda's familiar VTEC valve timing.

It produced 68 horsepower, and 67 lb-ft of torque at 4,800rpm--numbers boosted to 73 hp and 83 lb-ft at a much reduced 1,500rpm thanks to an electric motor.

Low-viscosity oil helped reduce friction, as did the lack of a balancer shaft, usually used to smooth out the uneven beat of 3-cylinder units. It also featured lean-burn technology to reduce fuel use, though emissions regulations mean lean-burn is no longer used due to higher oxides of nitrogen.

With a five-speed manual, the first-generation Insight is rated at 53 mpg combined (49 mpg city, 61 mpg highway) by the EPA.